Grate



Patented Oct. 29, 1946 UNIT-ED STATES PATENT 10F F ICE- L`Fly Ash `Arrestor"Corporation, aoorporation of Alabama l Application February 5, 1943,. Serial-No.-.474,795 701mm. (01.'-1126--1635 This .inventionkrelates to furnace grates particularly, lto the class employed in .furnaceswith forced draftand which Aare subject to intense heat, `andhasfor an object the provision of .an article o'f the character designated .which rshall be simple ofdesign, extremely sturdy, vand provided with -especially iicient heat dissipating means.

Aefur'ther .object of .my .invention is to provide acast iron grate withsheet. steel metalrins joined integrally. theretov .bycasting-the grate. around .the fins.

A further .objectof myinvention is to provide a .castiron grate with integrally .corrugated fins cast in same and-improvedmeansior supporting the gratein .theffurnaee 'Asfis .wellknownin vtheart vto which my inventionrelatesv gratesin.,forced. draft furnaces, especially .Wherea .thin re andspreader stokers are employed, are subject to'intense heat and often burnout-or break. -Iiha-ve found that by providing a plurality of rows of sheet steel fins extending from end to end of the grates and to which the grates are joined by casting the strength of the grates is materially increased and the heat dissipating effect of the ns is such that the grates have an indefinite life. In addition, air for combustion may be passed over the corrugated fins and heated. By attaching trunnions for the grates to the ns, they are afforded an extremely sturdy support which, being remote from the fire,

is not subject to extremes of heat. To afford additional security I provide projections on the sides of the fins where they are cast into the grates.

A grate embodying features of my invention is illustrated in the accompanying drawing forming a part of this application in which:

Fig. 1 is a top plan view;

Fig. 2 is a longitudinal section taken along the line II-II of Fig. 1; and

Fig. 3 is a transverse section taken along the line III-III of Fig. 1. l

Referring to the drawing my improved grate comprises a substantially flat cast iron body portion I provided with downwardly flaring air openings II therethrough. 'I'he grate is mounted over the usual wind box I2, so that air under pressure in the wind box passes upwardly through the openings II in the grate to support combustion, as is well understood.

Cast integrally with the grate is a plurality of corrugated sheet steel fins I3 which extend from end to end of the grate and are relatively closely spaced, the rows of ns being positioned along .'2 the rows of ,openingsl I. `In the making of the grate, ythe fins I3 'are 'joined integrally with the gratefbeinginserted in the 'sand'mold with'the pattern'before the castiron portionI'U is poured, and left protruding from the sand so lthat the molten cast iron is poured around them. "In order to insure .a strong .juncturebetwe'en thexi'insand the .castiron 'body I 0, '.I may Aprovide projections I'4 projecting from the sides ,of the 'fins 'where they extend .intofthe cast ironbody "-I'0. 'These projections may be `'in the form ogf smallpins which are passed through suitable "holes in the iinsbefore the bodyportionis'v poured. Thens I '3 .arepreferablymafde "fromstandar'd corrugated sheet. steelof about one-.eighthinch thickness and may vextend downwardly under -the grate from six `.to..tenfinches, .depending on the rating o'f the boiler furnace, .or'intensityiof heat'to which thel grates.maybesubjected [In 4designing .the .grate '.I .provide varadiating fin surface six'timesthe area of the upper surface of the grates, based on a calculated maximum heat release of 370,000 B. t. u. per hour per square foot of grate area. If a greater heat release is involved the iin surface is increased in direct proportion to the increase in heat release.

It will be seen by reference to Fig. l of the drawing that the fins I3, being corrugated, afford not only increased radiating surface, but provide an extremely sturdy beam structure for the support of the grate. The grate is supported from trunnions I6 which are joined to bars I'I which in turn extend entirely across the end of the grate and are welded to the ends of the fins I3. The trunnions I6 rest in bearings I8 which in turn are suitably Supported, as at I9, from supports positioned in the wind box I2. By reason of this means of support, even though the cast iron body of the grate be broken, the usefulness of the grate is not gone as it is supported from the fins and not from the body of the grate.

In case the grate is. to be employed as a dump grate, I weld a bar 2| across the bottoms of the fins I3 and secure an arm 22 thereto provided with a hole 23 to which suitable linkage (not shown) may be connected for dumping the grate.

The fins I3, in a grate constructed according to my invention, function to add strength to the grate and to protect it from heat. They distribute the heat from hot spots on the grate and thus minimize temperature stresses resulting from hot spots. The added distributing surface of the fins insures that no limited area on the grate shall become overheated. The fins providing .many times the radiating surface of the grate alone, distribute their heat to the air passing up through the grate from the wind box l2 and thus none of the heat to which the grates are subjected is lost, but is used for combustion of the fuel. Also the fins, being made from mild steel and securely joined to and forming a part of the grate, add many times the strength of the body portion Ill alone and provide an excellent means of support for the body portion I0. Even though the body portion be entirely broken, the support for the grate is not impaired and its usefulness not impaired.

From the foregoing it will be apparent that I have devised an improved grate which is simple' of design and economical of manufacture and one capable of withstanding rigorous service.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, Without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. A cast iron furnace grate comprising a body portion having a plurality of sheet metal ns spaced throughout their lengths from adjacent fins embedded therein on the under side thereof and extending from end to end of the grate, and supporting trunnions welded on to the fins at the ends of the grates.

2. A cast iron furnace grate having a plurality of corrugated sheet metal fins spaced throughout their lengths from adjacent fins integrally joined on the under side thereof extending from end to end of the grate, pins extending through each of the fins where it is joined to the grate at intervals throughout the length thereof for securing the ns in place in the grate, a bar extending across 4 the grate at each end thereof and welded to the ns, and a trunnion on each of the bars.

3. A furnace grate comprising a plurality of corrugated sheet metal fins spaced throughout their lengths from adjacent ns, a perforate body portion of cast iron cast about one edge of the fins, and means for supporting the grate by the ns. Y t

4. A furnace grate comprising a plurality of corrugated sheet steel fins spaced throughout their length from adjacent ns, a body portion of cast iron cast about one edge of the fins and having uniformly spaced holes between the fins, a bar extending across the grate at each end thereof and welded to the fins only, and a trunnion on each of the bars.

5. In a furnace grate, a plurality of sheet steel fins spaced throughout their length from adjacent fins, a cast iron body cast about one edge of the ns leaving the major portion of the width of said fins extending beyond the body, there being uniformly spaced holes through the body between the fins for the passage of air through the grate, and a'trunnion at each end of the grate secured directly to the fins.

6.1m a furnace grate, a plurality of sheet metal fins spaced throughout their length from adjacent fins, a cast iron body cast about one edge of the fins leaving the major portion of the width of said finsextending beyond the body, there being uniformly spaced holes through the body between the ns for the passage of air through the grate, a bar extending across the grate at each end thereof and welded to the fins, and a trunnion on each of the bars. I

'7. A grate, as set forth in claim 6 in which the fins are made of corrugated sheet steel and the holes through the grate body are disposed in sinuous rows paralleling the corrugations of the fins.

ELLIS W; BULLOCK. 

